JP2010182923A - Wafer handling robot device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive wafer handling robot device eliminating static electricity charged in a semiconductor wafer, and protecting a device, and having a simple structure; and a robot hand. <P>SOLUTION: This wafer handling robot device includes: a robot body; a robot hand holding part arranged on the robot body and electrically insulated from the robot body; this robot hand arranged on the robot hand holding part for transporting a semiconductor wafer; a resistive element for electrically connecting the robot body to the robot hand; a control device connected to the robot body for controlling the robot hand; and an earthing means to earth the robot body and the control device. The electric resistance of the resistive element is larger than the electric resistance of the robot body including the control device and the earthing means, and is desirably 10<SP>3</SP>-10<SP>6</SP>Ω. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wafer handling robot apparatus for handling semiconductor wafers.

  In the manufacturing process of semiconductors and liquid crystal display devices, static electricity may be charged on the thin substrate of the semiconductor wafer. When the wafer handling robot device handles the semiconductor wafer with the robot hand, electrostatic discharge occurs, There is a risk that the device may be destroyed or an electrostatic failure such as malfunction of a process device or a robot may occur due to generation of electromagnetic noise.

  In a wafer transfer device that handles a semiconductor wafer with a robot hand and transfers it to a semiconductor manufacturing device or semiconductor inspection device, the robot control device may fail due to the above causes, resulting in a malfunction or stoppage of the robot. is there.

  On the other hand, for example, Patent Document 1 discloses a static elimination technique in which a robot hand has an ionized gas ejection hole and has an electrostatic removal function by ejecting ionized gas from the ionized gas ejection hole.

  Patent Document 2 discloses a technique for protecting a robot and a robot control device from malfunction and destruction due to static electricity by giving a robot hand a high resistance value.

JP 2000-083732 A JP 2008-147241 A

  The wafer handling apparatus with a static electricity removing function disclosed in Patent Document 1 requires an ionized gas generator that generates ionized gas and a gas passage mechanism that guides the generated ionized gas to the robot hand and ejects it. For this reason, the structure as a wafer handling apparatus is complicated and expensive.

  In addition, the robot hand and wafer handling apparatus disclosed in Patent Document 2 must be manufactured so that the robot hand has a desired resistance value. For this reason, although the method of coating the surface of the robot hand to give a resistance value is taken, there is a problem that the coating is peeled off during use of the apparatus and adheres to the semiconductor wafer, thereby contaminating the semiconductor wafer. Furthermore, if the robot hand is manufactured by controlling the surface resistance value to a desired value, the cost increases.

  In view of the above-described problems, the present invention provides a wafer handling robot apparatus and a robot hand that can neutralize static electricity charged on a semiconductor wafer, protect the apparatus, and have a simple configuration and are inexpensive. With the goal.

  A wafer handling robot apparatus according to the present invention includes a robot body, a robot hand holding unit provided in the robot body and electrically insulated from the robot body, and a semiconductor wafer provided in the robot hand holding unit. A robot hand, a resistance element that electrically connects the robot body and the robot hand, a control device that is connected to the robot body and controls the robot hand, and an earth that grounds the robot body and the control device Means. An electrical resistance of the resistance element is larger than an electrical resistance of the robot body including the control device and the grounding means.

Further, another wafer handling robot apparatus according to the present invention includes a robot main body, a robot hand holding unit provided in the robot main body and electrically insulated from the robot main body, and a semiconductor provided in the robot hand holding unit. A robot hand for transferring a wafer; and a resistance element for electrically connecting the robot body and the robot hand. The electric resistance of the resistance element is 10 ³ Ω to 10 ⁶ Ω.

  According to the present invention, even when a semiconductor wafer is transported, even when the wafer is charged, static electricity can be released to the ground through the robot body during handling by the robot hand. It can protect against malfunction and destruction. In addition, since no special device or material is required for static elimination of the wafer and protection of the robot main body and the control device, the configuration is simple and can be manufactured at low cost.

1 is a schematic view of a wafer handling robot apparatus according to an embodiment of the present invention. The equivalent circuit diagram regarding the electrical resistance of the wafer handling robot apparatus by the Example of this invention. The specification determination table | surface of the resistance element in the Example of this invention. The equivalent circuit diagram of a wafer handling robot apparatus and a wafer used for calculation of the discharge time in the Example of this invention.

  Embodiments of the present invention will be described with reference to the drawings. First, an outline of a wafer handling robot apparatus according to an embodiment of the present invention will be described using the schematic diagram of the wafer handling robot apparatus shown in FIG.

  A semiconductor wafer (hereinafter referred to as a wafer) 16 is accommodated in a resin case 17. At this time, the wafer 16 may be charged with a high electrostatic voltage.

  The wafer handling robot apparatus includes a robot main body 11, a telescopic multistage arm 12 installed on the robot main body 11, a hand holding unit 18 installed at the tip of the multistage arm 12, and a tip of the hand holding unit 18. And a resistance element 2 that electrically connects the multistage arm 12 and the robot hand 1.

  The hand holding unit 18 is made of an insulating material or coated so as to have an insulating property, and the multistage arm 12 and the robot hand 1 are electrically insulated.

  The robot hand 1 has a low surface resistance value and is conductive, and can discharge static electricity charged on the wafer 16 during handling.

  The resistance element 2 may be anything as long as it has a resistance value as will be described later, and the lead wire is fixed in close contact with the robot hand 1 and the multistage arm 12 with screws or bolts.

  Further, the wafer handling robot apparatus has a control device 13. The control device 13 controls the operation of the wafer handling robot device such as the transfer and handling of the wafer 16. The control device 13 may be provided in the robot body 11.

  The robot body 11 and the control device 13 are installed on the device base 14 and are grounded via the device base 14 to a ground 15 that is a grounding means.

  The wafer 16 is handled by the robot hand 1. At this time, the robot hand 1 picks up the wafer 16 or grips the periphery of the wafer 16 to prevent the wafer 16 from dropping from the robot hand 1.

  The static electricity charged on the wafer 16 flows through the robot hand 1, the resistance element 2, the multistage arm 12, the robot body 11, and the control device 13 to the ground 15 via the device base 14, and is eliminated (hand). Since the holding part 18 is insulated, it is not energized).

  As described above, the robot hand 1 in contact with the wafer 16 is a conductor in order to reduce the surface electrical resistance. On the other hand, the electric resistance value of the resistance element 2 is made extremely higher than the electric resistance values of the robot hand 1, the multistage arm 12, the robot body 11, and the control device 13. Specifically, as described later, 10 kΩ to 10 MΩ is desirable. As a result, the voltage of static electricity applied to the robot body 11 and the control device 13 is kept low, and the value of the flowing current is reduced to protect the robot body 11 and the control device 13 from static electricity. The electrostatic voltage applied to the robot body 11 and the control device 13 needs to be lower than the withstand voltage of the electronic components used in the robot body 11 and the control device 13.

  The robot hand includes a type that sucks the back surface of the wafer 16 and an edge chuck type that grips the peripheral edge of the wafer 16. In any type, by reducing the surface electrical resistance of the robot hand 1 in direct contact with the wafer 16 and increasing the electrical resistance value of the resistance element 2, the wafer 16 can be protected against static electricity.

  FIG. 2 shows an equivalent circuit relating to electrical resistance of the wafer handling robot apparatus according to this embodiment. In this equivalent circuit, the electrical resistance Rr of the robot body 11 is the electrical resistance of the drive circuit of the robot body 11, and the electrical resistance Rc of the control device 13 is the electrical resistance of the internal circuit of the control device 13. In this equivalent circuit diagram, the multi-stage arm 12, the device base 14, and the electrical resistance of the ground 15 as a ground means are ignored. If these electric resistances cannot be ignored, these electric resistance values may be included in the electric resistance values of the robot body 11 and the control device 13.

  The electrostatic voltage Vs charged on the wafer 16 is first applied to the electric resistance Rh of the robot hand 1 and the electric resistance Rd of the resistance element 2. The voltage V applied to the robot body 11 and the control device 13 is based on the electrical resistance of the entire system (the electrical resistance Rh of the robot hand 1, the electrical resistance Rd of the resistance element 2, and the electrical resistance of the robot body 11 from the electrostatic voltage Vs. Rr and the combined resistance of the electric resistance Rc of the control device 13) and the combined resistance of the electric resistance Rr of the robot body 11 and the electric resistance Rc of the control device 13 are reduced. That is, the voltage V applied to the robot body 11 and the control device 13 is extremely smaller than the electrostatic voltage Vs due to the extremely high electric resistance Rd value (preferably 10 kΩ to 10 MΩ) of the resistance element 2.

The voltage V applied to the electric resistance Rr of the robot main body 11 and the electric resistance Rc of the control device 13 is obtained by Expression (1).
V = Vs · (Rr · Rc / (Rr + Rc)) / (Rh + Rd + Rr · Rc / (Rr + Rc)) (1)
Here, the electric resistance Rh of the robot hand 1 is 0.1Ω, the electric resistance Rr of the robot body 11 is 0.1Ω, the electric resistance Rc of the control device 13 is 0.1Ω, the electric resistance Rd of the resistance element 2 is 100 kΩ, When the voltage Vs is 25 kV (a generally considered upper limit value of the electrostatic voltage charged on the wafer), the voltage V is 0.0125V. This voltage V is lower than the withstand voltage of general electronic components used in the robot body 11 and the control device 13, and this electronic component can be protected from electrostatic breakdown and malfunction. When there is a control device in the robot body 11, it can be protected in the same manner.

In addition, the current I flowing through the entire system due to static electricity is
I = Vs / (Rh + Rd + Rr · Rc / (Rr + Rc))
And flows to the ground 15 and is neutralized.

  As described above, the electric resistance Rd of the resistance element 2 is much higher than the electric resistances Rr and Rc of the robot main body 11 and the control device 13, so that the voltage applied to the robot main body 11 and the control device 13 is sufficiently low. can do.

  For this reason, the electronic components of the robot body 11 and the control device 13 are protected from destruction or malfunction due to static electricity charged on the wafer 16.

  Next, a method for determining the electric resistance value of the resistance element 2 will be described.

  FIG. 3 is a specification determination table of the resistance element 2 in this embodiment. This specification determination table changes the electric resistance value of the resistance element 2, and the control unit (the robot body 11 and the control unit when the static electricity charged on the wafer 16 is applied to the robot hand 1 for each electric resistance value. The voltage applied to the control circuit in the device 13 and the time until discharging (discharge time) are shown. The electric resistance value of the resistance element 2 can be determined based on the applied voltage and the discharge time in the specification determination table.

  In the specification determination table shown in FIG. 3, the voltage applied to the control unit can be obtained from Equation (1). The values described above were used for the parameters on the right side of Equation (1).

  The discharge time was calculated using an equivalent circuit representing the wafer handling robot apparatus and the wafer 16 in a simplified manner as shown in FIG. The equivalent circuit of FIG. 4 includes a capacitor 42 that models the charged wafer 16, a switch 41 that models contact between the robot hand 1 and the wafer 16, and a resistor 44 that models the resistance element 2. . The capacitor 42 holds an initial charging voltage V 0 corresponding to the electrostatic voltage Vs charged on the wafer 16. When the switch 41 is closed, a current 43 flows from the capacitor 42. Thereby, the robot hand 1 and the wafer 16 are in contact with each other, and the discharge of the electrostatic voltage Vs charged on the wafer 16 is simulated.

In the equivalent circuit of FIG. 4, when the voltage of the capacitor 42 (the charged voltage of the wafer 16) is Vc (t), the discharge is started by closing the switch at time t = 0 (the robot hand 1 at time t = 0). Is in contact with the wafer 16), the voltage Vc (t) of the capacitor 42 at the time t can be calculated by the equation (2).
Vc (t) = V0 · exp (−t / R · C) (2)
Here, R is the electric resistance value of the resistor 44, and C is the capacitance of the capacitor 42 (capacitance between wafers). From equation (2), the time required for the charged wafer 16 to discharge can be determined. In this embodiment, it is assumed that the wafer 16 is discharged when the charging voltage Vc (t) of the wafer 16 reaches the order of millivolts.

  The discharge time shown in FIG. 3 is 25 kV, which is a generally considered upper limit value of the electrostatic voltage charged on the wafer, and R (the resistance value of the resistor 44 modeled on the resistance element 2) is the above-described electric current. 100 kΩ, C, which is the same as the resistance Rd, is obtained as 60 pF.

  When the specification determination table shown in FIG. 3 is viewed, the voltage applied to the control unit is 1.25 V or less (the range indicated by the desirable voltage value region 31) when the electrical resistance value of the resistance element 2 is 10 kΩ or more. The breakdown voltage of the IC, which is an electronic component of the control unit, is lower than the withstand voltage so that the electronic component is not destroyed or malfunctioned. Therefore, in the case of the present embodiment, the electrical resistance value of the resistance element 2 is desirably 10 kΩ or more.

On the other hand, when the electric resistance value of the resistance element 2 is 10 MΩ or less, the discharge time is 10 ⁻³ s or less (a range indicated by a desirable discharge time region 32). When the discharge time is in the desired discharge time region 32, the charge removal time is short and the charge removal effect is enhanced.

  Therefore, the resistance value in the range (desired resistance value region 33) where the desired voltage value region 31 and the desired discharge time region 32 cross each other is the optimum value of the electric resistance Rd of the resistance element 2. In the present embodiment, the optimum value of the electric resistance Rd of the resistance element 2 can be obtained as 10 kΩ or more and 10 MΩ or less.

  DESCRIPTION OF SYMBOLS 1 ... Robot hand, 2 ... Resistance element, 11 ... Robot main body, 12 ... Multistage arm, 13 ... Control apparatus, 14 ... Apparatus base, 15 ... Ground, 16 ... Wafer, 17 ... Resin case, 18 ... Hand holding part, DESCRIPTION OF SYMBOLS 31 ... Desired voltage value area | region, 32 ... Desired discharge time area | region, 33 ... Desired resistance value area | region, 41 ... Switch, 42 ... Capacitor which modeled the charged wafer, 43 ... Current which flows from a capacitor | condenser at the time of discharge, 44 ... Resistive element Modeled resistance, Vs ... electrostatic voltage charged on the wafer, V ... voltage applied to the robot body and the controller, Rh ... electric resistance of the robot hand, Rd ... electric resistance of the resistance element, Rr ... drive circuit of the robot body Electrical resistance, Rc: Electrical resistance of the internal circuit of the control device, I: Current flowing through the entire system, V0: Initial charging voltage, t: Time, Vc ( ) ... the voltage of the capacitor at time t, R ... electric resistance value of the resistance of the resistive element was modeled, C ... electrostatic capacitance of the capacitor.

Claims (3)

The robot body,
A robot hand holding unit provided in the robot body and electrically insulated from the robot body;
A robot hand that is provided in the robot hand holding unit and carries a semiconductor wafer;
A resistance element for electrically connecting the robot body and the robot hand;
A control device connected to the robot body for controlling the robot hand;
A grounding means for grounding the robot body and the control device;
The wafer handling robot apparatus, wherein an electric resistance of the resistance element is larger than an electric resistance of the robot body including the control device and the grounding means. The robot body,
A robot hand holding unit provided in the robot body and electrically insulated from the robot body;
A robot hand that is provided in the robot hand holding unit and carries a semiconductor wafer;
A resistance element for electrically connecting the robot body and the robot hand;
An electric resistance of the resistance element is 10 ³ Ω to 10 ⁶ Ω.   3. The wafer handling robot apparatus according to claim 1, wherein the robot hand holding unit is made of an insulating material.

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